Apparatus for bevelling wire blanks

ABSTRACT

For providing an improved deformability of wire blanks (such as chain link blanks) during noncutting shaping, there is performed a bevelling step on the wire blank simultaneously from two opposite sides in the same blank zone, while leaving unaffected a flat cross-sectional portion adjacent the blank axis. This bevelling step is subsequently repeated at least once in the same zone in a direction set off not more than 90* with respect to the bevelling direction of the first bevelling step.

United States Patent Esser et al.

Oct. 21, 1975 APPARATUS FOR BEVELLING WIRE BLANKS [75] Inventors: PaulEsser; Emil Mayer; Paul Rahn,

all of Cologne, Germany [73} Assignee: Meyer, Roth & PastorMaschinenfabrik GmhH, Cologne, Germany [22] Filed: Sept. I8, 1973 [2]]Appl. No.: 398,534

[30] Foreign Application Priority Data Sept, 18, 1972 Germany 2245771[52] US. Cl. 72/404; 59/23; 225/96; 225/103 [51] Int. Cl. 821.] 13/02[58] Field of Search r. 72/404, 324, 338; 83/519; 59/1.18,23,35,71, 75,77; 225/l03, 94, 96

[56] References Cited UNITED STATES PATENTS l,l38,2ll 5/1915 Graham M59/77 l,990,57l 2/1935 Stahl 59/23 1,994,794 3/1935 Stahl 59/I 2.025.557l2/l935 Stahl 7. 59/35 277L735 ll/l956 Wilson 59/18 3,114,276 l2/19633,626,746 l2/l97l 3,7l4 776 2/l973 Lange 59/23 Primary ExaminerLowell A.Larson Assistant Examiner(]ene Pi Crosby Attorney, Agent, orFirm-Spencer & Kaye [57] ABSTRACT For providing an improveddeformability of wire blanks (such as chain link blanks) duringnoncutting shaping, there is performed a bevelling step on the wireblank simultaneously from two opposite sides in the same blank zone,while leaving unaffected a flat cross-sectional portion adjacent theblank axis. This bevelling step is subsequently repeated at least oncein the same zone in a direction set off not more than 90 with respect tothe bevelling direction of the first bevelling step.

2 Claims, 6 Drawing Figures U.S. Patent 0:.21,197s SheetlofZ 3,913,374

FIG. 3

US. Patent Oct. 21, 1975 Sheet 2 of2 3,913,374

FIG. 5

DIN

APPARATUS FOR BEVELLING WIRE BLANKS BACKGROUND OF THE INVENTION Thisinvention relates to apparatus for bevelling continuously fed wireblanks, particularly chain link blanks.

According to a known method, as disclosed, for example, in US. Pat. No.2,025,557, the bevelling is performed in such a manner that eachbevelled blank end has two bevelled surfaces arranged symmetrically toone another in a V-shape. These surfaces form identical angles with theaxis of the blank and converge in a crest that intersects the blankaxis. There is also known an apparatus for performing this method. Suchapparatus, as disclosed, for example, in -U.S. Pat. No. 1,994,794,comprises two cooperating V-shaped cutters which are advancedsimultaneously and from opposite directions towards the blank. Thepurpose of bevelling the blank ends in the above manner is to ensurethat during the welding together of the blank ends bent into a C-shapeto form a chain link, the fusion proceeds from the adjoining, lengthwisecontacting, cutter-shaped crests in an outward direction. In this mannerimpurities which may be formed by scaling, oxidation or the like duringthe welding process, are displaced outwardly into the weld during thewelding operation and particularly during forging. Subsequently, theimpurities are ground or filed away with the weld burr.

It has since been found to be more advantageous if the fusion occursfrom the inside outwardly, not in the manner taught by theafore-mentioned prior art but by maintaining unaffected by the bevellinga residual cross-sectional portion which is symmetrical to the blankaxis, so that during forging the expulsion of the flowing metal into theweld occurs not only in a direction perpendicular to the crests, butalso uniformly in all radial directions (German Laid-Open ApplicationNo. 1,602,632). The apparatus for accomplishing such a result is,however, quite complex because it includes four bevelling tools arrangedin a frame at 90 with respect to one another. These tools are advancedtowards the axis of the blank one after the other in the plane of theblank cross section in radial directions disposed at 90 to one another.Not only is such an apparatus complex and its bevelling operation muchtoo time consuming to be connected to a chain link bending machine ofusual rhythm, but also, unsymmetrical deformations are very likely tooccur.

There is further known a similar apparatus as disclosed, for example, inGerman Gebrauchsmuster (utility patent) No. 1,920,278 wherein two knivesthat cut notches in a blank are advanced in a common holderperpendicularly and symmetrically with respect to the blank axis. Thefrontal faces of the knives have a cutting edge and between the twocutting edges there is provided a play, so that an unaffectedcross-sectional portion in the wire blank is maintained.

SUMMARY OF THE INVENTION It is an object of the invention to provide animproved method and apparatus of the afore-outlined type which are freeof the above-discussed disadvantages, whereby the bevelling process isperformed on the wire blank symmetrically, very rapidly and by means ofsimple devices.

This object and others to become apparent as the specificationprogresses, are achieved by the invention according to which, brieflystated, a bevelling is first ef fected in a known manner simultaneouslyfrom two opposite sides in the same zone of the blank substantiallyperpendicularly to the blank axis, while maintaining unaffected a flatcross-sectional portion adjacent the blank axis, and subsequently,substantially in the plane of the same cross section, the same bevellingprocess is repeated at least once, in a direction shifted not more thanin the circumferential direction of the blank with respect to thedirection of the preceding bevelling step.

The invention is based on the discovery that when working with theearlier discussed know apparatus which has two bevelling tools advancedfrom opposite directions perpendicularly to the blank axis, the materialflows at the locus of working in a particular manner, as explained laterin the specification.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a side elevational view of awire blank, such as a chain blank, taken in the direction of advance ofone of the bevelling tools and showing the locus of working.

FIG. 2 is a sectional view taken along line Il-II of FIG. 1.

FIG. 3 is a top plan view of the blank shown in FIG. 1, with bothbevelling tools visible.

FIG. 4 is a perspective schematic view of a preferred embodiment of theinvention.

FIG. 5 is a schematic side elevational view of another preferredembodiment of the invention.

FIG. 6 is a schematic side elevational view of still another preferredembodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Turing now to FIGS. 1, 2 and 3,there are shown bevelling tools 10 which, as they are advanced towardsthe longitudinal axis of the blank 11 through positions a-bc-d-e, causematerial particles of the planes f, g, h, i, j, k of the blank 11 to becompressed in succession. By virtue of the volume constant and thereaction of the volume elements of the planes f-k with respect to oneanother, the material flows in the axial direction from the middle ofthe blank cross section. At the same time, the cross sections l-m-n-o-ptend to move away from one another. The first still missing compressionin the planes k-j-i prevents the parallel shift of the planes l-mn-o-pin the vicinity of the outer surface of the blank. Thus, in this zonethere is generated a tension in the axial direction with a volume shiftin the same direction, whereby in this zone, by virtue of the volumeconstant, material flows inwardly from the outer surface of the blank.The consequence of the above-described occurence is the appearance ofthe constrictions 12 of the blank cross section. These oppositely lyingconstrictions 12 are oriented 90 with respect to the operationaldirection of the bevelling tools. These constrictions which may beclearly observed during operation, have heretofore not been given anyattention.

The invention utilizes this phenomenon by providing a second bevellingstep during which the be velling tools engage the blank in the zones ofthese constrictions. As the bevelling tools are advanced in the courseof this second bevelling step, they first eliminate the tensional stresspresent and subsequently generate a compression stress with axialdisplacement of material. In this manner there are achieved anadditional flow-readiness of the material and an expansion of thebevelling process for a greater cross section and/or a greater strength.

Accordingly, the process according to the invention is particularlyadapated for the bevelling of wire blanks made of high carboncontainingand high-alloyed materials which, because of their hardness andbrittleness, make noncutting metal shaping particularly difficult.

The process according to the invention may undergo severalmodifications. Thus, it is not critical whether the bevelling tools areadvanced exactly in the cross sectional plane of the blank or at a smallangle thereto. Further, it is also not critical to operate along thecrosssectional plane of the blank merely with two pairs of work toolsstaggered at 90 in a radial direction; often it is necessary to makebevelled faces that have more than four frustopyramidal bevels. Thus, itis only exemplary to perform the bevelling process twice: the bevellingsteps each time with a change of direction may be performed four times.A three-step operation is also possible but is probably less practical.

In certain cases the method according to the inven tion may be somodified that instead of providing two knife pairs which in successionwork on the stationary blank at the same location, the knife pairs arearranged spaced from one another along the length of the blank andoperate simultaneously. It is true that in this manner the structurallength of the apparatus is increased but at the same time the operatingtime is substantially decreased and also, the structure of the apparatusis simplified. Such a device for performing the method according to theinvention is illustrated schematically in FIG. 4 and will now bedescribed in detail.

The blank 11 is advanced intermittently in the direction of arrow I3.The first bevelling step is performed thereon by the first bevellingtools 10, whereas the second bevelling step is performed thereon by thesecond bevelling tools spaced from the first bevelling tools 10 alongthe blank axis at a distance 14 which corresponds to the length of oneblank. The tool pair 10' which works in the cross-sectional plane 16perpendic ularly to the blank axis [5 is set off by 90 with respect tothe tool pair 10. Since each tool, as shown in FIG. 3, has a leadingedge face 17 and two lateral faces 18 arranged symmetrically to oneanother in a V-shape, there is eventually obtained a bevel 19 having aquadratic frustopyramidal surface 20, four frustoconical surfaces 21 anda circular base surface 22. Since the bevelling operation according tothe invention may be effected in such a manner that the leading blank llsnaps off as a result of the second bevelling step, the frustopyramidalsurface is not always completely smooth, but has an uneven character andmay even have a slightly prismatic form. Such a phenomenon is notnecessarily disadvantageous for initiating the fusion process from theinside outwardly. Nevertheless, it is possible without difficulty todesign the edge face 17 at each tool to be more or less wide or to sodesign the cutting tool that the lateral faces 18 converge into acutting edge.

Turning now to FIG. 5, there is shown a particular design ofthe toolsaccording to the invention, concerning in particular the support of thebevelling tools. Each bevelling tool 10" is supported in a tool carrier23 which forms part of a tool holder 24 and which is pivotal about anaxis 25 in the direction of the arrow 26. The advance of the tool holder24 is effected exclusively in the direction of the arrow 27 while theblank 11' is held stationary. By virtue of the support of the tools 10"in their pivoting carriers 23 according to the invention, thedisplacement of the material in the blank occurs, during the noncuttingshaping, advantageously in the direction of the arrow 28 in which theblank 11" should have a freedom of motion. In this manner it is possibleto avoid radial material shifts.

The resetting ofthe bevelling tools 10" is effected by a reset spring 29so that in the withdrawn position of the tool support 24 the bevellingtools 10" abut a stop face 30 forming part of the work tool holder 24.

Another embodiment of the invention is schematically illustrated in FIG.6. In this embodiment, the bevelling tools 10" can be advancedexclusively in the direction of the arrow 27. The bevelling tools 10have a lateral surface 18' which extends perpendicularly to the blankaxis and a lateral face 18" which forms an angle with the surface 18'.In this case also, the material of the blank flows exclusively in thedirection of the arrow 27 and radial material shifts in the direction ofarrow 28 are avoided if the blank 11 is held stationary and a freedom ofmotion is ensured for the blank 11". The avoidance of such radialmaterial shifts in the direction of the arrow 28 is of particularsignificance for accomplishing that the constrictions 12 which aregenerated in the course of the first bevelling operation are fullydeveloped as described earlier to thus achieve, according to theinvention, the substantial deformability even of materials whichotherwise are difficult to shape.

It will be understood that the above description of the presentinvention is susceptible to various modifications, changes andadaptations and the same are intended to be comprehended within themeaning and range of equivalents of the appended claims.

We claim:

1. An apparatus for bevelling a wire blank simultaneously atdiametrically opposite sides from successively different directions,comprising at least two pairs of bevelling tools; the bevelling tools ofeach pair being arranged to move simultaneously and in oppositedirections to one another into engagement with said wire blank; thedirection of advance of each tool towards said blank being normal to thelongitudinal axis of the blank; cutting faces provided on each tool,said cutting faces being arranged symmetrically with respect to anycross-sectional plane of said blank; a separate tool holder associatedwith each bevelling tool for carrying the same, each tool holder beingmovable towards and away from said axis in a direction normal thereto;means for pivotally securing each bevelling tool to its associatedholder for a pivotal motion of the bevelling tool about an axis that isnormal to and spaced from the axis of said blank; an abutment providedon each tool holder and cooperating with the tool to determine therefora position of rest; and spring means engaging each tool holder and theassociated tool for urging the tool against said abutment.

2. An apparatus for bevelling a wire blank simultaneous at diametricallyopposite sides from successively different directions, comprising atleast two pairs of bevelling tools: the bevelling tools of each pairbeing arranged to move simultaneously and in opposite direc tions to oneanother into engagement with said wire tool to its associated holder fora pivotal motion of the bevelling tool about an axis that is normal toand spaced from the axis of said blank; an abutment provided on eachtool holder and cooperating with the tool to determine therefor aposition of rest; and spring means engaging each tool holder and theassociated tool for urging the tool against said abutment.

1. An apparatus for bevelling a wire blank simultaneously atdiametrically opposite sides from successively different directions,comprising at least two pairs of bevelling tools; the bevelling tools ofeach pair being arranged to move simultaneously and in oppositedirections to one another into engagement with said wire blank; thedirection of advance of each tool towards said blank being normal to thelongitudinal axis of the blank; cutting faces provided on each tool,said cutting faces being arranged symmetrically with respect to anycrosssectional plane of said blank; a separate tool holder associatedwith each bevelling tool for carrying the same, each tool holder beingmovable towards and away from said axis in a direction normal thereto;means for pivotally securing each bevelling tool to its associatedholder for a pivotal motion of the bevelling tool about an axis that isnormal to and spaced from the axis of said blank; an abutment providedon each tool holder and cooperating with the tool to determine therefora position of rest; and spring means engaging each tool holder and theassociated tool for urging the tool against said abutment.
 2. Anapparatus for bevelling a wire blank simultaneous at diametricallyopposite sides from successively different directions, comprising atleast two pairs of bevelling tools: the bevelling tools of each pairbeing arranged to move simultaneously and in opposite directions to oneanother into engagement with said wire blank; the direction of advanceof each tool towards said blank being normal to the longitudinal axis ofthe blank; each bevelling tool has a first cutting face extending normalto said axis and a second cutting face arranged at an angle with respectto said first face; a separate tool holder associated with eachbevelling tool for carrying the same, each tool holder being movabletowards and away from said axis in a direction normal thereto; means forpivotally securing each bevelling tool to its associated holder for apivotal motion of the bevelling tool about an axis that is normal to andspaced from the axis of said blank; an abutment provided on each toolholder and cooperating with the tool to determine therefor a position ofrest; and spring means engaging each tool holder and the associAted toolfor urging the tool against said abutment.